| 摘要 |
A graphic processing unit includes a texture memory storing a plurality of two-dimensional slices that volume data is sliced or two-dimensional textures; a texture mapping unit sampling the two-dimensional texture with the two-dimensional slices; and a calculation process performing volume rendering by using sampling values of the two-dimensional textures. Therefore, a graphic processing unit in which a three-dimensional texture mapping function is not provided can improve rendering speed when performing the volume rendering. [Reference numerals] (205) Emit rays; (210) Calculate the position of a sample point; (215) Position of the sample point = Position of voxel ?; (220) Read a brightness value in the position of the voxel at a texture memory; (225) Project the sample point into two planes corresponding to two-dimensional slices; (230) Calculate the position of two projected points and deliver the same to a mapping unit; (235) Calculate the brightness value in the two projected points by using a two-dimensional texture mapping function; (240) Deliver the brightness value in the two projected points to a calculation processor; (245) Calculate the brightness value in the sample point by using linear beams; (250) Accumulate the brightness value in the calculated sample point; (255) Emission of rays to one pixel is completed?; (260) Emission of rays to all pixels is completed?; (AA) Start; (BB,FF,GG) Yes; (CC,DD,EE) No; (HH) End |
